James Posted July 24, 2003 Share Posted July 24, 2003 I had a problem yesterday when my desk (Gemini) crashed out on me, three times in a row - in about as many minuites) in the middle of a scene. It was fin before and fine after but I lost the state when the desk died. In case this happens again - and as a shor term fix before I can save to replace it - does anyone know of a way to mod strand F&D interfaces so that they "remember" a state if valid D54 dissapears. I know most DMX interfaces offer this but suspect D54 being analogue can't. Anyone able to put me right or recomend a good scrap merchant and cheep (and lighter) replacement (in roughly that order) James Link to comment Share on other sites More sharing options...
Stu Posted July 24, 2003 Share Posted July 24, 2003 I think D54 might be able to remember the last sent instructions, our MX48 and STM/JTM racks certainly did when I was at college, the lights would stay up for about 2 minutes before fading off slowly - certainly enough time for you to get the desk to work again. Mind you this was a while ago so I can't remember everything about it! Stu Link to comment Share on other sites More sharing options...
James Posted July 24, 2003 Author Share Posted July 24, 2003 well bugger me sideways with a corkscrew if that wasn't a speedy responce - Thanks Stu Now I know it might be possible I feel an email to Jon Primrose coming on - Unless anyone has more info to hand??? James Link to comment Share on other sites More sharing options...
Stu Posted July 24, 2003 Share Posted July 24, 2003 I'll pass on the whole corkscrew bit :blink: ;) The only reason I remember is that our trusty MX48 crashed in the middle of the show once and I had plenty of time to do the problem sorting etc etc so I know it's capable.... And the dimmers weren't even digital so it should be able to remember... I'm sure one of the detailed looks into how D54 works might lead to a reason why it could hold last sent data... Something to do with the continiously emitting data stream?! Anyway who knows. Yep perhaps Strand Archive might be the answer, or Strand Support? Stu Link to comment Share on other sites More sharing options...
James Posted July 24, 2003 Author Share Posted July 24, 2003 getting the desk back up didn't seem to be a problem - power off power on and a second later the last state was restored. ;) it's just the two seconds or so of "artisticly valid blackout" (Well it was the gravedigger scene from hamlet and there wasn't a lot of state up and there was so much spill from the building I can't think anyone could have noticed much...) Hadn't thought of trying Strand Tech Support - and I don't know why as they were very helpful when I had a problem many years ago with my first desk (AMC) Link to comment Share on other sites More sharing options...
gareth Posted July 24, 2003 Share Posted July 24, 2003 Yep perhaps Strand Archive might be the answer, or Strand Support?Try speaking to John Wright at Strand tech support. He's a boffin when it comes to Strand control kit, and I'm sure he'll be able to help. Link to comment Share on other sites More sharing options...
Bryson Posted July 24, 2003 Share Posted July 24, 2003 I'll second that about John Wright - he's a very helpful and nice man too. If anyone knows Duncan Wood's contact details (I've lost 'em) he's also a master of all things Gemini. Anyway. I'm off on holiday now...see you folks in a few weeks. ;) Link to comment Share on other sites More sharing options...
Tom Baldwin Posted July 24, 2003 Share Posted July 24, 2003 strand F&D interfaces so that they "remember" a state if valid D54 dissapears. I know most DMX interfaces offer this but suspect D54 being analogue can't.I don't see a problem with D54 kit remembering it's state just because it's analogue. The basic idea of a D54 decoder is to sample the sequence of levels presented on the signal wire, and store each presented level on a buffer feeding the individual outputs. So the hardware to maintain an analogue output level even when it's not present on the control line is there... Things that might make it not work for you, might include:- the "hold" portion of the sample and hold circuit only being designed to store the output voltage for a very short time (maybe a handful of D54 clock cycles). While in principle you could add hardware which read the voltage on the hold circuit, and amplified and refreshed it, it's probably not hardware already existing in the demux.- the nature of the crash on the desk: if it stops outputting levels, but continues to clock the signal (I know D54 has no dedicated clock line, I assume clocking is achieved via a sync pulse? Anyone?), then the decode will sample and hold the (now zero) levels being output. Sorry I don't have any specifics on the Strand F&D interfaces. Tom Link to comment Share on other sites More sharing options...
JohnK Posted July 24, 2003 Share Posted July 24, 2003 If anyone knows Duncan Wood's contact details (I've lost 'em) he's also a master of all things Gemini. Indeed, Duncan is your man for Gemini type stuff, contact me off list if you want his details (I don't think he'd approve of me posting them on an open forum) HTHJohn lights "at" johnkendall "dot" com Link to comment Share on other sites More sharing options...
James Posted July 24, 2003 Author Share Posted July 24, 2003 - the nature of the crash on the desk: if it stops outputting levels, but continues to clock the signal (I know D54 has no dedicated clock line, I assume clocking is achieved via a sync pulse? Anyone?), then the decode will sample and hold the (now zero) levels being output. Hmm - I had other things on my mind than the nature of the crash at the time but everything dissapeard - no monitor display no desl display - nothing but the lluminated neon at mains inlet. but as you say it could have beem outputting valid D54 at the time. thanks Oh and JohnK if you could PM me Duncan's contact details (email) then that would be great thanks. James Link to comment Share on other sites More sharing options...
Stu Posted July 24, 2003 Share Posted July 24, 2003 Ducan posts alot on R.A.T.S so you might be able to find him on there... Stu Link to comment Share on other sites More sharing options...
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